Field of the invention
The invention relates to the field of sensing such as for example biosensing. More particularly, the present invention relates to methods and systems for multiplexed, i.e. simultaneous, optical sensing or characterizing samples, such as for example used in sequencing applications.
Background of the Invention
For a number of sensing applications, such as for example different biosensing applications, the need for multiplexed processing is high. In several applications, a large number of sensing events needs to be performed for obtaining an accurate characterization of a sample. One example of such an application whereby a large number of sensing events are required is sequencing, although also other applications benefit from multiplexed sensing. To obtain sufficiently efficient characterisation systems, there is a constant pressure from the market for increasing the number of sensing events that can be obtained with a microfluidic chip per day. In order to increase this number, the number of sensing sites can be increased. The density of sensing sites that can be introduced on a microfluidic chip can be high, e.g. more than 104, more than 105, more than 106, . . . .
Whereas in principle it would be possible to provide a separate sensor for each of the sensing sites, this would not result in a practical solution, especially not when a large density of sensing sites is used. Consequently, sensing techniques are preferred that allow multiplexed sensing based on the same measurement. Different measurement techniques that have been used in the past are fluorescence based imaging, chemiluminescence imaging, electrical measurements, optical detection making use of white light sources or tunable lasers, etc.
Although a number of different detection techniques have already been suggested for improving multiplexed detecting, further improvement is needed if high speed processing, e.g. at a rate of at least 100 Gbp/day or even better at a rate of at least 300 Gbp/day, is to be obtained.